Standalone FP8 won't load automatically

I’m trying to load some swfs into Flash Player 8 by double clicking them in Windows Explorer, but they’re all still opening in Flash Player 7. I’ve tried switching the default registered application for swfs to Flash Player 8, but Windows won’t have it. I’ve had to resort to opening FP8 and launching the swfs from there, which is a bit of an annoyance. Any ideas?